ivy.el (ivy-done): Allow ivy-dispatching-done to exit with no cands

ivy.el (ivy-done): Allow ivy-dispatching-done to exit with no cands

Example of use:

(defun ivy-recentf-with-last-input (_x)
  (ivy-read "Recentf: " recentf-list
            :action (lambda (f)
                      (with-ivy-window (find-file f)))
            :initial-input ivy-text
            :caller 'ivy-recentf))

(ivy-set-actions t '(("r" ivy-recentf-with-last-input "recentf")))

The input may match no candidates, but it's still good for
`ivy-recentf-with-last-input', since it uses `ivy-text' instead of
`ivy--current'.